Fig. 4

Schematic phylogeny, scaled to geological time, of selected coelurosaurs showing the pattern of acquisition of key modifications of the skin. The phylogeny is the most likely of the maximum likelihood models, based on minimum-branch lengths (mbl) and transitions occurring as all-rates-different (ARD). Claws and footpads are considered primitive in coelurosaurs. Available data indicate that modified keratinocytes, and continuous shedding, originated close to the base of the Maniraptora; this is predicted to shift based on future fossil discoveries towards the base of the Coelurosauria to include other feathered taxa